John McCain had dire words for supporters at a recent event: A Donald Trump nomination could give him problems with Hispanic voters in his bid for a sixth term as Arizona senators.

"If Donald Trump is at the top of the ticket, here in Arizona, with over 30 percent of the vote being the Hispanic vote, no doubt that this may be the race of my life," McCain is heard saying on a recording of the event obtained by Politico.

"If you listen or watch Hispanic media in the state and in the country, you will see that it is all anti-Trump. The Hispanic community is roused and angry in a way that I've never seen in 30 years."

The event was held last month, before Ted Cruz and John Kasich dropped out of the race and Trump's win in Indiana left him as the presumptive GOP nominee, and McCain's statements differed from his public stance, which is that Trump won't hurt his election chances.

McCain said in late April that his brand in Arizona is strong enough to to stand up to anti-Trump fall out. He has been endorsed by the U.S. Hispanic Chamber of Commerce, marking the group's first candidate endorsement, and has opposed Trump on immigrants for months.

But earlier in the month, at the fundraiser, he admitted Trump could be a problem.

"Frankly there's an element of nativism in it as well, as you know. The first wedge that Donald Trump had that gave him notoriety was, 'Build a wall,' 'rapist,' 'murderers,' etc.," McCain said at the Phoenix fundraiser in April. "And so, this is going to be a tough campaign for me."

McCain's worries reflect a growing concern among Republicans defending the two dozen seats up for grabs this year, particularly in states like Arizona, where Latinos reflect 22 percent of eligible voters; Florida, with 18 percent; Nevada, 17 percent; Colorado, 14 percent; and Illinois, 10 percent, according to Pew Research figures.

All of those states are facing Senate elections, leaving the Republican candidates to have to decide whether to stick with Trump, who has faced Latino ire since the beginning of his campaign, or to break away and risk appearing disloyal to their party.

Nevada Sen. Dean Heller won in Nevada in 2012 after distancing himself from GOP nominee's talk of "self-deportation," and told Politico that Nevada Rep. Joe Heck, who is running to replace retiring Senate Minority Leader Harry Reid, can also win, as he has a "great relationship" with Hispanics. However, he admitted that it will take "more work."

In McCain's case, Kica Matos director of immigrant rights and racial justice at the Center for Community Change Action, commented that there is a "price to be paid for belonging to a party that explicitly endorses a very virulent anti-immigrant agenda. You can't divorce John McCain from the person who is more likely than not the Republican presidential nominee."